Social dimension to consumption

The Economist on the way that we buy things that are popular. There is clearly a certain comfort in knowing that others have bought the same thing. Some of the costs of finding out about quality are removed.
Swarming the shelves:

"And the psychology that works in physical stores is just as potent on the internet. Online retailers such as Amazon are adept at telling shoppers which products are popular with like-minded consumers. Even in the privacy of your home, you can still be part of the swarm. "

This can be linked to the puchase of popular items and means of communication. The star system.